I'm now planning to put my work directories (lots of small codes) in SD cards so that I can manage them conveniently.

What is the best filesystem for SD card? I will access my SD cards through a built-in cardreader in my laptop. Because I have to access them both in Windows and in Gentoo, so I think I have only several choises.

I performed several tests using fs_mark on a SanDisk 16GB SD card (Class10, w/r up to 30MB/s and 45MB/s).